The present invention pertains generally to automated production processes and machinery and, more particularly, to machinery for automated manufacture and assembly of multiple components into a subassembly or finished product.
Innerspring assemblies, for mattresses, furniture, seating and other resilient structures, were first assembled by hand by arranging coils or springs in a matrix and interconnecting them with lacing or tying wires. The coils are connected at various points along the axial length, according to the innerspring design. Machines which automatically form coils have been mated with various conveyances which deliver coils to an assembly point. For example, U.S. Pat. Nos. 3,386,561 and 4,413,659 describe apparatus which feeds springs from an automated spring former to a spring core assembly machine. The spring or coil former component is configured to produce a particular coil design. Most coil designs terminate at each end with one or more turns in a single plane. This simplifies automated handling of the coils, such as conveyance to an assembler and passage through the assembler. The coil forming machinery is not easily adapted to produce coils of alternate configurations, such as coils which do not terminate in a single plane.
The timed conveyance of coils from the former to the assembler is always problematic. Automated production is interrupted if even a single coil is misalign in the conveyor. The conveyor drive mechanism must be perfectly timed with operation of the coil former and a transfer machine which picks up an entire row of coils from a conveyor and loads it into the innerspring assembler.
The spring core assembly component of the prior art machines is typically set up to accommodate one particular type of spring or coil. The coils are held within the machine with the base or top of the coil fit over dies or held by clamping jaws, and tied or laced together by a helical wire or fastening rings. This approach is limited to use with coils of particular configurations which fit over the dies and within the helical lacing and knuckling shoes. Such machines are not adaptable to use with different coil designs, particularly coils with a terminal convolution which extends beyond a base or end of the coil. Also, these types of machines are prone to malfunction due to the fact that two sets of clamping jaws, having multiple small parts and linkages moving at a rapid pace, are required for the top and bottom of each coil.
The present invention overcomes these and other disadvantages of the prior art by providing novel machinery for complete automated manufacture of formed wire innerspring assemblies from wire stock. In accordance with one aspect of the invention, there is provided an automated innerspring assembly system for producing innerspring assemblies having a plurality of wire form coils interconnected in an array, the automated innerspring assembly system having at least one coil formation device operative to form wire stock into individual coils configured for assembly in an innerspring assembly, and operative to deliver individual coils to a coil conveyor, a coil conveyor associated with the coil formation device and operative to receive coils from the coil formation device and convey coils to a coil transfer machine, a coil transfer machine operative to remove coils from the coil conveyor and present coils to an innerspring assembler, an innerspring assembler operative to receive and engage a plurality of coils arranged in a row, to position a received row of coils parallel and closely adjacent to a previously received row of coils, to fixedly compress two adjacent rows of coils in a fixed position and interconnect the adjacent rows of coils with fastening means, and to advance interconnected rows of coils out of the assembler and receive and engage a subsequent row of coils.
In accordance with another aspect of the invention, there is provided a system for automated manufacture of innerspring assemblies having a plurality of generally helical coils interconnected in a matrix array, the system having a coil formation device operative to produce individual coils for an innerspring assembly, the coil formation device having a pair of rollers for drawing wire stock into a coil forming block, a cam driven forming wheel which imparts a generally helical shape to the wire stock fed through the coil forming block, a guide pin which sets a pitch to the generally helical shape of the coil, and a cutting device which cuts a formed coil from the wire stock, the coil forming block having a cavity in which a terminal convolution of a coil having a diameter less than a body of the coil fits during formation of the coil, and into which the cutting device extends to cut the coil from the wire stock at an end of the terminal convolution, at least one coil head forming station having one or more punch dies for forming non-helical shapes in coils, the coil head forming station having a jig which accommodates a terminal convolution of a coil which extends beyond a portion of the coil to be formed in a non-helical shape by the coil head forming station, a tempering device which passes an electrical current through a coil, and a geneva having a plurality of arms, each arm having a gripper operative to grip a coil from the coil forming block, advance the coil to a coil head forming station and to the tempering device, and from the tempering device to a coil conveyor; a coil conveyor operative to convey coils from the coil formation device to a coil transfer machine, the coil conveyor having a plurality of flights slidably mounted upon a track which extends along upper and lower sides of the conveyor, each flight connected to a main chain mounted upon sprockets at each end of the coil conveyor, each flight having a clip configured to engage a coil, an indexer flight drive mechanism operative to advance the flights along the conveyor tracks, a coil orientation device operative to uniformly orient each of the coils in the flight clips, and a braking mechanism for retarding the advance of flights along the conveyor tracks; a coil transfer machine having a plurality of arms, each arm having a gripper operative to grip a coil and remove it from a flight clip of the conveyor, and present the gripped coil to an innerspring assembler, the coil transfer movably mounted proximate to the conveyor and to the innerspring assembler; an innerspring assembler operative to interconnect rows of coils presented by the coil transfer machine, the innerspring assembler having two sets of upper and lower coil-engaging dies mounted upon carrier bars, whereby rows of coils can be inserted into the innerspring assembler between upper and lower coil-engaging dies by the coil transfer machine, the innerspring assembler further comprising an elevator assembly operative to vertically translate the carrier bars toward and away from terminal ends of coils in the innerspring assembler, and an indexer assembly operative to horizontally translate the carrier bars, whereby the two sets of upper and lower coil-engaging dies and corresponding carrier bars can converge and retract relative to rows of coils in the innerspring assembler, and can laterally exchange positions to advance rows of coils out of the innerspring assembler, the innerspring assembler further comprising a lacing wire feeder operative to feed a lacing wire through an opening formed by adjacent coil-engaging dies and about portions of coils engaged in the dies to thereby interconnect rows of coils.
These and other aspects of the invention are herein described in particularized detail with reference to the accompanying Figures.